CS Linux and CS/AIX support for Power7 systems

Answer

Communications Server for Linux, Communications Server for AIX, and communications Server for Data Center Deployment levels will run on Power 7 systems, with the following restrictions:

• CS Linux V6.4, CS/AIX V6.4, and CS DCD V7 are supported on Power 7 systems using Power 6/6+ compatibility mode and Power 7 mode.
• PTF level 6.4.0.2 or later is required. The latest maintenance may be obtained at:
• CS Linux v6.4 - Latest Fixpack
• CS/AIX v6.4 - Latest PTFs
• No PTF is required for CS DCD V7.

Other configuration and planning considerations:

Any IP related activity, such as Enterprise Extender (HPR/IP), TN3270 Server, TN Redirector, and Remote API Client/Server connections, are fully supported. When using IP related connectivity, no special configuration is required.

When using CS/AIX on a virtual system we recommend moving to a total IP solution, because the IP stack is handled by AIX for high availability, while LLC2 is not.

LLC2 connections require specific configuration: the ethernet adapter must be carefully configured to bridge LLC2 (802.3 ethernet) traffic. The Power7 hardware is designed for virtual support of operating systems; if Communications Server is running in a virtual guest and LLC2 is configured, then the ethernet adapter used for LLC2 must be configured to bridge LLC2 traffic. Be aware that virtual systems allow adapters to be shares, and LLC2 needs to be configured with this knowledge.

Within the AIX server that acts as a Host for the Power7 system, the mapping of guests to virtual interfaces will need to be performed. Each guest will need to have its own MAC address for the LLC2 connection.

Also, the virtual system environment does not guarantee the accuracy of the realtime clock or processing cycles for the guest systems. For Communications Server, that will affect any connections over which HPR is used. One of the main features in the CS Linux and CS/AIX 6.4 release is the support for HPR connections on virtual systems.

A new HPR algorithm called Progressive ARB has been introduced by VTAM V1 R11 that does not use the real-time clock to determine transmission rates and status responses. On virtual systems, this means an improvement of about 25% throughput under normal circumstances and assurance that a sudden temporary lack of CPU cycles will not effect overall throughput. Without this support, any stress on CPU, network resources, or memory access could cause packets to get resent, which could impact performance significantly.

Communications Server does not detect whether it is running within a virtual system or on dedicated hardware.

• For HPR, if the system it connects to supports Progressive ARB, then the connection will use Progressive ARB. Only Communications Server V6.4 and later provides this support.
• For LLC2, SNA frames will be transmitted; if the virtual ethernet adapter is properly bridged, the frames will reach their destination, and arriving frames will be routed to the proper virtual system.

When planning to run Communications Server in a virtual environment, we recommend that the V6.4 level be used. In order to automatically recover for lost frame situations due to LLC2 resource contention in virtual environments, we recommend that HPR be enabled on LLC2 connections. HPR is enabled by default. Enterprise Extender connections require the use of HPR, so it can not be disabled for those connections.